Compared to viewing a distant object, a human viewing an object held within five centimeters of the eye requires a lens that ________.
A) has been flattened, as a result of contraction of the ciliary muscles
B) has been made more spherical, as a result of contraction of the ciliary muscles
C) has been flattened, as a result of relaxation of the ciliary muscles
D) has been made more spherical, as a result of relaxation of the ciliary muscles

Question

Quizplus · Accepted Answer

When a human views an object held within five centimeters of the eye, the ciliary muscles contract to increase the curvature of the lens, making it more spherical. This allows for proper refraction of light and clear vision. However, when viewing a distant object, the ciliary muscles are relaxed and the lens is flattened.

Compared to Viewing a Distant Object, a Human Viewing an Object